proposal for important! options

conans/model/options.py

@@ -17,6 +17,7 @@ class _PackageOption:
     def __init__(self, name, value, possible_values=None):
         self._name = name
         self._value = value  # Value None = not defined
+        self.strong = False
         # possible_values only possible origin is recipes
         if possible_values is None:
             self._possible_values = None
@@ -27,10 +28,11 @@ def __init__(self, name, value, possible_values=None):
     def dumps(self, scope=None):
         if self._value is None:
             return None
+        strong = "!" if self.strong else ""
         if scope:
-            return "%s:%s=%s" % (scope, self._name, self._value)
+            return "%s:%s%s=%s" % (scope, self._name, strong, self._value)
         else:
-            return "%s=%s" % (self._name, self._value)
+            return "%s%s=%s" % (self._name, strong, self._value)
 
     def copy_conaninfo_option(self):
         # To generate a copy without validation, for package_id info.options value
@@ -182,12 +184,19 @@ def __setitem__(self, item, value):
 
     def _set(self, item, value):
         # programmatic way to define values, for Conan codebase
+        strong = item[-1] == "!"
+        item = item[:-1] if strong else item
+
         current_value = self._data.get(item)
         if self._freeze and current_value.value is not None and current_value != value:
             raise ConanException(f"Incorrect attempt to modify option '{item}' "
                                  f"from '{current_value}' to '{value}'")
         self._ensure_exists(item)
-        self._data.setdefault(item, _PackageOption(item, None)).value = value
+        v = self._data.setdefault(item, _PackageOption(item, None))
+        new_value_strong = strong or (isinstance(value, _PackageOption) and value.strong)
+        if new_value_strong or not v.strong:
+            v.value = value
+            v.strong = new_value_strong
 
     def items(self):
         result = []

conans/test/integration/options/options_test.py

@@ -666,3 +666,69 @@ def test_transitive_options_conanfile_py_create(self, client):
         client.save({"app/conanfile.py": conanfile})
         client.run("create app --build=missing")
         self.check(client, False)
+
+
+class TestStrongOptions:
+    @pytest.mark.parametrize("pkg", ["liba", "libb", "app"])
+    def test_strong_options(self, pkg):
+        c = TestClient()
+
+        liba = GenConanfile("liba", "0.1").with_option("myoption", [1, 2, 3])
+        libb = GenConanfile("libb", "0.1").with_requires("liba/0.1")
+        app = GenConanfile().with_requires("libb/0.1")
+        if pkg == "liba":
+            liba.with_default_option("myoption!", 2)
+        elif pkg == "libb":
+            libb.with_default_option("*:myoption!", 2)
+        elif pkg == "app":
+            app.with_default_option("*:myoption!", 2)
+        package_id = textwrap.dedent("""
+            def package_id(self):
+                self.output.info(f"MYOPTION: {self.info.options.myoption}")
+            """)
+        liba = str(liba) + textwrap.indent(package_id, "    ")
+
+        c.save({"liba/conanfile.py": liba,
+                "libb/conanfile.py": libb,
+                "app/conanfile.py": app})
+        c.run("export liba")
+        c.run("export libb")
+
+        c.run("graph info app -o *:myoption=3")
+        assert "liba/0.1: MYOPTION: 2" in c.out
+
+        # And the profile can always strong-override the option
+        c.run("graph info app -o *:myoption!=3")
+        assert "liba/0.1: MYOPTION: 3" in c.out
+
+    def test_profile_shows_strong(self):
+        c = TestClient()
+        c.run("profile show  -o *:myoption!=3")
+        assert "*:myoption!=3" in c.out
+
+    def test_strong_options_recipe_priority(self):
+        c = TestClient()
+
+        liba = GenConanfile("liba", "0.1").with_option("myoption", [1, 2, 3, 4])\
+                                          .with_default_option("myoption!", 1)
+        libb = GenConanfile("libb", "0.1").with_requires("liba/0.1")\
+                                          .with_default_option("*:myoption!", 2)
+        app = GenConanfile().with_requires("libb/0.1").with_default_option("*:myoption!", 3)
+
+        package_id = textwrap.dedent("""
+            def package_id(self):
+                self.output.info(f"MYOPTION: {self.info.options.myoption}")
+            """)
+        liba = str(liba) + textwrap.indent(package_id, "    ")
+
+        c.save({"liba/conanfile.py": liba,
+                "libb/conanfile.py": libb,
+                "app/conanfile.py": app})
+        c.run("export liba")
+        c.run("export libb")
+
+        c.run("graph info app")
+        assert "liba/0.1: MYOPTION: 3" in c.out
+
+        c.run("graph info app -o *:myoption!=4")
+        assert "liba/0.1: MYOPTION: 4" in c.out